| As the fourth major crop,potato(Solanum tuberosum L.)occupies an important position in agricultural production.Potato tuber is used for asexual reproduction except for edible.To improve the yield and quality of potato,the study of the formation and development of tuber is of great significance.Potato tuberization is a complicated process,which is affected by many factors,including light,temperature,nutritional substances and hormones.Jasmonic acid(JA)has been suggested to play a prominent role in the regulation of potato tuberization process.To ascertain the effect of JA on the development of potato tuber,the diploid potato(DM)test-tube seedlings were used as experimental materials.By using different concentrations(0,0.5,5,50 ??)JA treated the potato stems,the morphological,physiological and comparative proteomic responses of potato tuber were investigated.The physiology and molecular mechanism of JA regulation of potato tuber development were clarified in our study.The results obtained in this study as follows:1.The influences of JA on tuber morphology and physiology.The supply of 0.5 and 5 ?? JA could enhance the tuber size,fresh and dry weight accumulations of potato tuber.However,the tuber size,fresh and dry weight accumulations of potato tuber were inhibited after treated with 50 ?? JA.Under 0.5,5 and 50 ?? JA treatments,the tuberization ratioes were increased to 2.6,4.7 and 5.1 times,respectively.The tuber length to width ratio on the concentrations of 0.5,5 and 50 ?? JA were decreased by 19.8 %,21.9 % and 27.3 %,respectively.JA could ahead of potato tuberization time,and it was obviously be found that stems treated with 50 ?? JA began to form tubers on the 5th day.The starch contents of potato tuber were decreased by 21.1 % and 5.4 % on the concentrations of 0.5 and 5 ?? JA,respectively.Under 50 ?? JA treatment,the content of starch was increased by 28.3 %.JA had an advantage of promoting the formation of the soluble sugar content of potato tuber.Under 0.5,5 and 50 ?? JA treatments,the soluble sugar contents of potato tuber were increased to 1.9,4.1 and 2.9 times,respectively.Compared to the control,the reducing sugar contents of potato tuber on the concentrations of 0.5 and 5 ?? JA were decreased by 16.9 % and 14.2 %,respectively.The reducing sugar content on the concentration of 50 ?? JA was elevated by 6.5 %.JA inhibited the activity of lipoxygenase in potato tubers.Under 0.5,5,and 50 ?? JA treatments,the activities of lipoxygenase were reduced by 43 %,78.4 % and 87.8 %,respectively.2.Comparative proteomics analysis of potato tuber development in vitro regulated by JA.The proteomics analysis showed that there was no significant difference in the number of protein spots among the treatments of different JA concentrations(0,0.5,5,50 ??).The protein spots numbers detected in each treatment were 620±13.1,611±19.9,608±3.1 and 616±10.1,respectively.A total of 41 proteins pots changed under JA treatments,among which 14 points were new proteins that emerged after JA treated.The MALDI-TOF/TOF MS analyses led to the identification of the 41 differentially expressed proteins that categorized into classes,including metabolism-related proteins,storage-related proteins,protein translation and degradation-related proteins,cell defense-related proteins,chaperone,channel protein and cell wall-related protein.3.NAD-dependent malate dehydrogenase was up-regulated after 5 ?? JA treated,which could provide energy for the growth of tuber by promoting the tricarboxylic acid cycle.Under JA treatments,fructokinase was first up-regulated and then was down-regulated,which suggested that JA could affect potato tuber starch content by influencing the expression of fructokinase.When treated with JA,fructose-bisphosphate aldolase was up-regulated,indicating that JA may accelerate carbohydrate metabolism by participating in the process of glycolysis.Under JA treatments,some kunitz-type protease inhibitors were up-regulated,which indicated that JA helped to accumulate storage protein in potato tuber.JA inhibited the expression of actin-7 protein that might change the potato tuber shape by inhibiting cell wall synthesis and cell shape maintenance. |
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